This paper presents high-efficiency high-gain GHz power amplifiers (PAs) for wireless communications. Two class-B PAs are designed and verified in µm CMOS mixed-signal/RF process provided by TSMC. The PAs employs cascode topologies with wideband multi-stage matchings. The singlestage cascode PA is designed for a high power added efficiency (PAE) of while the gain is dB over the -3 dBbandwidth between GHz and GHz. The two-stage cascode PA is targeted for a high gain of dB while it exhibits a peak PAE of . Supplied by V supply voltages, the PAs consume DC powers of mW and 9 mW, respectively. | VNU Journal of Science: Comp. Science & Com. Eng., Vol. 33, No. 1 (2017) 8-15 A Model for Real-time Concurrent Interaction Protocols in Component Interfaces Van Hung Dang∗, Trinh Dong Nguyen, Hoang Truong Anh VNU University of Engineering and Technology, Hanoi, Vietnam Abstract Interaction Protocol specification is an important part for component interface specification. To use a component, the environment must conform to the interaction protocol specified in the interface of the component. We give a powerful technique to specify protocols which can capture the constraints on temporal order, concurrency, and timing. We also show that the problem of checking if a timed automaton conforms to a given real-time protocol is decidable and develop a decision procedure for solving the problem. Received 16 January 2017; Accepted 27 February 2017 Keywords: Interaction Protocol, Timed Automata, Region Graph, Component Interface. 1. Introduction* An interaction protocol specified in the interface of a component is a precondition on the temporal order on the use of services from the component. Fail to satisfy this precondition may lead to a system deadlock [2]. In real-time systems, when a service from a component takes a considerable time to carry out, too frequently calling to this service may lead to the error state too. So, we need to specify the minimum duration between two consecutive calls to the services that takes time, and this also plays a role of precondition on the consecutive calls to those services in the interaction protocols. Another possibility that we need to consider when specifying this kind of time constraints is that a component may be able to provide services in parallel. In this case, time constraints do not apply to concurrent services. Let us consider an example. Imagine that we have a software component that provide accesses to two files: one stores the information about products and the other stores the information about customers. To access to .
